// Basic test which checks the number of documents returned, keys examined, and documents
// examined as reported by explain.

t = db.jstests_explain6;
t.drop();

t.ensureIndex( { a:1, b:1 } );
t.ensureIndex( { b:1, a:1 } );

t.save( { a:0, b:1 } );
t.save( { a:1, b:0 } );

explain = t.find( { a:{ $gte:0 }, b:{ $gte:0 } } ).explain( true );

assert.eq( 2, explain.executionStats.nReturned );
assert.eq( 2, explain.executionStats.totalKeysExamined );
assert.eq( 2, explain.executionStats.totalDocsExamined );

// A limit of 2.
explain = t.find( { a:{ $gte:0 }, b:{ $gte:0 } } ).limit( -2 ).explain( true );
assert.eq( 2, explain.executionStats.nReturned );

// A $or query.
explain = t.find( { $or:[ { a:{ $gte:0 }, b:{ $gte:1 } },
                          { a:{ $gte:1 }, b:{ $gte:0 } } ] } ).explain( true );
assert.eq( 2, explain.executionStats.nReturned );

// A non $or case where totalKeysExamined != number of results
t.remove({});

t.save( { a:'0', b:'1' } );
t.save( { a:'1', b:'0' } );
explain = t.find( { a:/0/, b:/1/ } ).explain( true );
assert.eq( 1, explain.executionStats.nReturned );
assert.eq( 2, explain.executionStats.totalKeysExamined );
